Should a prediabetic use glucose meter to monitor glucose after meals to learn which foods cause hi blood sugar to avoid further insulin resistance?

Maybe but it depends: While your suggestion is not currently part of ada guidelines & recommendations, if it will help you see result of your food choices & help you make better choices, then i think it's reasonable. In truth, your nutritionist can help you develop healthy eating habits w/o using a glucometer. For instance, check out the mediterranean diet. Don't forget to exercise regularly to reduce Insulin resistanc.